President Barack Obama on Wednesday strongly condemned the killing of the US ambassador to Libya
and three other embassy staff as an "outrageous attack" and ordered increased security at US diplomatic posts worldwide.

"I have directed my administration to provide all necessary resources to support the security of our personnel in Libya, and to increase security at our diplomatic posts around the globe," Obama said in a statement after the US diplomats were killed in a rocket attack on their car in Benghazi.

"While the United States rejects efforts to denigrate the religious beliefs of others, we must all unequivocally oppose the kind of senseless violence that took the lives of these public servants," he said.

US ambassador to Libya Christopher Stevens and three other embassy staff were killed in a rocket attack on Tuesday night that targeted his car in Benghazi, a Libyan official said on Wednesday.

"The American ambassador and three staff members were killed when gunmen fired rockets at them," the official in Benghazi told Reuters. Asked about the deaths, a US Embassy employee in Tripoli said: "We have no information regarding this." The employee said the embassy could confirm the death of one person.

The Libyan official said the US ambassador had been on his way to a safer venue after protesters attacked
the US Consulate in Benghazi and opened fire, killing a staff member, in protest at a US film that they deemed blasphemous to the Prophet Mohammad.

The film that sparked violence in Libya

The official said the ambassador and three other staff were killed when gunmen fired rockets at his car.

He said the US Embassy had sent a military plane to transport the bodies to Tripoli to fly them to the United States.

Gunmen assaulted the Benghazi compound on Tuesday evening, clashing with Libyan security forces, who withdrew under heavy fire. The attackers fired at the buildings while others threw handmade bombs into the compound, setting off small explosions. Small fires were burning around the compound.

Ambassador's car after the attack (Photo: Reuters)

The assault followed a protest
in neighboring Egypt
where demonstrators scaled the walls of the US embassy, tore down the American flag and burned it during a protest over the same film which they said insulted the Prophet Mohammad.

Following the spasm of attacks, the filmmaker, who identifies himself as an Israeli Jew, has gone into hiding.

Protesters in Cairo (Photo: AFP)

Writer and director Sam Bacile spoke on the phone Tuesday from an unidentified location. He remained defiant, saying Islam is "a cancer" and he wanted his film to make a political statement.

On Tuesday, US Secretary of State Hillary Clinton
confirmed the death of a US diplomat, who was not identified at the time, and condemned the attack on the Benghazi consulate.

Clinton further expressed concern that the protests might spread to other countries. She said the US is working with "partner countries around the world to protect our personnel, our missions, and American citizens worldwide."